1. Field of the Invention
This invention relates to motion vector detection apparatuses, and more particularly to a motion vector detection apparatus and a processing method of a motion vector as well as a program for causing a computer to execute the method wherein a block matching method is used.
2. Description of the Related Art
It is widely known that dynamic picture image data can be compressed using, when the dynamic picture image data is handled, a motion vector between frames of the dynamic picture image data. As one of techniques for detecting a motion vector, a technique generally called block matching is used. According to the block matching technique, a base frame and a reference frame which are two input images are used, and a correlation degree between a base block set in the base frame and each of a plurality of reference blocks set in a search region of a reference frame is determined. Then, a motion vector with respect to the base block is calculated based on that one of reference blocks which indicates the highest one of the determined correlation degrees.
In such an existing technique as just described, since a correlation degree between each of a plurality of reference blocks set in a reference frame and a base block is calculated for each reference frame, the processing amount is great and high power consumption is required. Therefore, a technique of varying the size of the search region in a reference frame based on two input images has been proposed. For example, a motion vector detection apparatus has been proposed wherein a search region is set based on a correlation degree between a base block of a base frame and a block at a predetermined position of a reference frame. One of such motion vector detection apparatus as just described is disclosed, for example, in Japanese Patent Laid-Open No. 2000-078580 (FIG. 2).